Explicit Declaration of Pureness and Throwness of Higher Order Ranges

["Nordlöw"]

Is it, in D today, possible to explicitly tag higher order ranges 
such as for example `map` with their pureness, safeness and 
throwness based on the corresponding properties on their function 
arguments such as `fun...`?

And is this motivated? now that the D compiler deduce these 
properties for us automagically?

I guess if we had some intricate IDE-integration with DMD/DCD or 
alike these properties could be automatically presented to the 
programmer for each range instantiation.